Tailoring surface charge distribution via lattice Cl-doping on Cu2O nanocubes for high-selectivity CO2-to-C2+ electroreduction via asymmetric C–C coupling

Despite utilization of state-of-the-art Cu-based catalysts, achieving high selectivity and stability in multicarbon (C 2+ ) compounds production through electrocatalytic CO 2 reduction reaction (CO 2 RR) remains a critical and challenging objective. Here we employ lattice chlorine-doped Cu 2 O nanocubes (Cl d -Cu 2 O NCs) with well-defined {100} facets as a model catalyst to demonstrate that halogen doping can serve as a versatile and effective strategy for modulating surface charge distribution, thereby enhancing asymmetric C–C coupling toward high-selectivity C 2+ products in CO 2 RR. Compared to Cl-free Cu 2 O NCs, Cl d -Cu 2 O NCs exhibit a greatly enhanced C 2+ Faraday efficiency, i.e., ∼85% at −1.1 V (versus the reversible hydrogen electrode). Additionally, the Cl d -Cu 2 O NCs demonstrate significantly enhanced long-term durability, attributed to better preservation of the cubic morphology and more stable Cu δ + states. In-situ electrochemical studies reveal that Cl d -Cu 2 O NCs facilitate the formation of the key asymmetric *COH and *OCCOH intermediates, ultimately leading to higher C 2+ products. Density functional theory (DFT) calculations confirm that the introduced Cl-dopants disrupt the charge balance of the Cu 2 O(100) surface, enriching the Cl-adjacent Cu atoms with more electrons compared to those near O atoms. This unbalanced charge distribution significantly reduces the free energy of the rate-determining step for asymmetric C–C coupling from the *CO to *OCCOH on Cl-doped Cu 2 O (100) surface, requiring only 1.04 eV, in contrast to 1.50 eV on pristine Cu 2 O(100) surface. This study provides valuable insights into the surface charge modulation of Cu 2 O catalysts via halogen doping for enhancing asymmetric C–C coupling and C 2+ production in CO 2 RR.